National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Mitochondrial complex III deficiency



Is complex III in the mitochondria itself or is it part of the body?  I am confused about where exactly it is and what function it has.


Where is mitochondrial complex III located in the body?

Our bodies are made of many cells, small sphere-like units that collectively form every organ and body part.  Each cell contains many, very small structures called mitochondria that produce energy for the cell.  Inside each mitochondria, there are tiny chemicals called proteins which interact with each other.  Complex III is the name of a group of proteins that work together inside the mitochondria.  So, there are many complex III proteins in every mitochondria, many mitochondria in every cell, and many cells in the body.
Last updated: 8/3/2012

What is the function of mitochondrial complex III?

Mitochondrial complex III works with other chemicals (called proteins) in the mitochondria to make energy for the cells in the body.  The specific job of complex III is to act as a kind of pump, moving small molecules from one compartment of the mitochondria to another.[1]
Last updated: 8/3/2012

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  1. Cooper GM and Hausman RE. The Cell: A Molecular Approach, 3rd Ed.. Washinton, DC: ASM Press; 2004;